The focus of this project in the Inorganic, Bioinorganic and Organometallic Chemistry Program is the organometallic chemistry of three transition metals: iron, ruthenium and osmium. Of particular interest are compounds of these metals in which oxygen or nitrogen atoms, or nitrogen-containing organic molecules, are bound to the metal. Results of the project are expected to provide an improved understanding of oxidation reactions mediated by metal complexes in organic chemistry and by metalloenzymes in living systems. Alkyl complexes of the iron triad metals in high oxidation states will be studied. Novel reaction chemistry of nitridoosmium(VI) and ruthenium(VI) will be exploited in cross-coupling reactions of organic halides with Grignard reagents. The syntheses of new oxo or nitrido metal complexes containing a second pi-donor ligand (oxo, sulfido, alkylimido, or alkylidene) will be undertaken, and the reactions of these new complexes with unsaturated organic molecules, two-electron donors and electrophiles will be examined. New types of heterobimetallic molecules will be synthesized which will be both coordinatively unsaturated and highly oxidized. These new heterobimetallic complexes are expected to show increased reactivity and selectivity in the oxidation of organic molecules, since they will be designed to bind substrate, activate it toward intramolecular atom transfer, and suppress competing electron transfer reactions. The cooperativity between the two metals may aid in the utilization of dioxygen as the secondary oxidant. A thorough study of the mechanism of the oxidation of alcohols by dioxygen, utilizing a previously-discovered bimetallic osmium-chromium complex, will be undertaken. Finally, previous work on the organometallic chemistry of ruthenium and osmium in high oxidation states will be extended to include oxidized alkyl iron complexes.
